Host mechanisms: are they the key to the various clinical outcomes of Helicobacter pylori infection?
It is unclear why Helicobacter pylori produces different diseases in different persons. High and low acid secretion rates probably contribute to duodenal ulceration and gastric carcinogenesis, respectively. Both of these changes seem to be corrected by eradicating Helicobacter pylori. We are therefore exploring the basic mechanisms and asking why patients react differently? Helicobacter pylori products and certain cytokines released in Helicobacter pylori gastritis release gastrin from G-cells but inhibit parietal cells. Also tumour necrosis factor alpha inhibits somatostatin-cells and interleukin 1 beta inhibits enterochromaffin-like cells. The net result is that antral gastritis tends to increase, whilst corpus gastritis tends to decrease acid secretion. Corpus atrophy further lowers acid through loss of parietal cells. Factors postulated to increase corpus gastritis include host genetics, early acquisition of Helicobacter pylori, more aggressive strains, poor general health and diets high in salt or lacking in antioxidant vitamins. Further research should address the interaction of bacterium, host and environment with a view to preventing the serious clinical outcomes.
Calam
J
J
Imperial College School of Medicine, Postgraduate Medical School, Hammersmith Hospital, London, England.
D016207:Cytokines / Q000378:metabolism; D004378:Duodenal Diseases / Q000378:metabolism / Q000382:microbiology / Q000473:pathology; D005744:Gastric Acid / Q000378:metabolism; D019863:Gastrin-Secreting Cells / Q000378:metabolism / Q000382:microbiology / Q000473:pathology; D016481:Helicobacter Infections / Q000209:etiology / Q000378:metabolism*; D016480:Helicobacter pylori / Q000472:pathogenicity*; D006632:Histamine / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D010295:Parietal Cells, Gastric / Q000378:metabolism / Q000382:microbiology / Q000473:pathology; D019864:Somatostatin-Secreting Cells / Q000378:metabolism / Q000382:microbiology / Q000473:pathology; D013272:Stomach Diseases / Q000378:metabolism / Q000382:microbiology / Q000473:pathology
D016207:Cytokines; D006632:Histamine